Before starting your collecting you should know about key issues.A key issue is just a comic in which something important happens.
Types of Key issues
1st/2nd/3rd appearance of [fill in character or fill in team]
1st in comic book appearance of [fill in character]
1st Cameo appearance of [fill in character]
1st cover of appearance of [fill in character]
Death of [fill in character]
Final issue of a comic
Important Event[battles/suit change/changes of leadership]
Origin of [fill in character]
Key issues are divided into two types Major Keys and Minor Keys. A major key would be the 1st appearance of character a minor key would be a suit change of a character.
Here’s where things get tricky when value is concerned, though a first appearance will always be a “major key” that doesn’t mean that it will defiantly be worth more than a “minor key”.
Popularity of a character weighs heavily on what has value and what doesn’t. Knowing and predicting what is and will be valuable is what makes collecting difficult and fun.
The first one is X-Men: The End #1 is the 1st appearance of Aliyah Bishop. The daughter of Warbird and Bishop from an alternate timeline. It is not worth as much as Batman Damned #1. Why is it controversial? It is DC’s R-rated label, and they had Bruce was naked and drawn anatomically correct.
This issue is not worth as much as Adam: Legend of the Blue Marvel #2. This issue is not a key issue, but it is from a comic book series that had a limited run less than 13,000 copies were ever made. So though not a key issue, it is still a rare and valuable comic.
Keys are important but watching for variants and limited series,can be just as important.